Capital Cities had a big 2013, vaulting to the top of the Alternative Songs chart and Billboard's Hot 100 top 10 with debut hit "Safe and Sound." The genre-bending single shot into the public conscious in large part due to its music video, which earned the duo a nomination for best music video at the 56th GRAMMY Awards.

For 2014, in addition to seeing if the GRAMMY nomination turns into a win, the Los Angeles indie rockers will take on their biggest challenge yet: opening for Katy Perry over 26 dates on her upcoming arena tour. While at the Sundance film festival this week, the duo stopped in at the Sonos Home Theater Lounge to chat with Billboard about that tour, calling it "an honor" but admitting that there were some definite butterflies.

"We're very excited to be doing this, and it's an honor to be, I guess, hand-selected by Katy Perry to open up her show," Ryan Merchant, one-half of the duo, said. "It means a lot for someone to feel like you'll be a good representation or part of the aesthetic she wants to portray before her show. So that's really cool, and it's a little bit scary, because it's going to be a huge 26-day arena tour. It's going to be a major step up from what we've been doing as far as playing big venues, going along for the ride with this big production."

As such, Merchant and bandmate Sebu Simonian have some nerves to spar against prior to the tour's start June 22 -- but in all, they're not too worried. "It's getting our creative juices flowing on how to make our show better," Merchant explained, "because we know it might not top Katy Perry's but it's gotta deliver something special."

Sundance Film Festival

The duo also spoke about its music video for "Safe and Sound," which has racked up over 63 million views on YouTube. According to Simonian, the video was shot at the Los Angeles Theatre, and Capital Cities knew right off the bat it potentially had something intriguing on its hands.

"When we started working on and developing ideas for the music video, we felt like we were onto something special," Simonian said. "The day of the shoot was at the Los Angeles Theatre, which was this historic, beautiful theater in L.A., and we brought 60-70 dancers that we discovered on Craigslist -- [which is] how we met. So all these dancers came in, and some semi-professional, some were amateurs, some were pro -- it was this really cool cultural clash happening during the video shoot, so we felt like there was something there."